1. Field of the Invention
The present invention relates to a digital signal storing apparatus and method, program recording medium, digital signal recording apparatus and method.
2. Description of the Related Art
The copyright protection system using the SCMS (serial copy management system) used in an MD (mini disc), DAT (digital audio tape recorder), etc. cannot prevent innumerable copies (for example, first-generation copies) from being made of an original digital signal. Therefore, when such a copyright protection system is applied in a currently available current personal computer (PC) connected to a network and other peripheral media than hard discs, a digital signal can be copied repeatedly in a fraudulent manner, and the conventional copyright protection system can scarcely protect the copy of a digital signal.
The conventional copyright protection system cannot prevent a digital signal purchased by a user from being perfectly copied innumerably without any degradation in quality.
To prevent such innumerable fraudulent copies of a digital signal, it is necessary that the digital copy once copied cannot be copied any longer.
Accordingly, the present invention has an object to overcome the above-mentioned drawbacks of the prior art by providing a digital signal storing apparatus and method, program recording medium, and a digital signal recording apparatus and method, adapted to prevent a copyrighted digital signal from being copied innumerably in a fraudulent manner.
The above object can be attained by providing a digital signal storage apparatus comprising according to the present invention:
means for reading a copyrighted digital signal;
means for setting a copy bit flag indicating whether there exists any digital signal identical to the copyrighted digital signal; and
means for storing the digital signal;
the flag setting means setting in a digital signal from the reading means a copy bit flag which indicates that there exists no digital signal identical to the copyrighted digital signal, and writing the copy bit flag to the storage means, or setting in a digital signal from the storage means a copy bit flag which indicates that there exists a digital signal identical to the copyrighted signal, and providing the digital signal as an output.
Also the above object can be attained by providing a digital signal storing method comprising, according to the present invention, the steps of:
reading a copyrighted digital signal;
setting in the read copyrighted digital signal a copy bit flag indicating whether there exists any digital signal identical to the copyrighted digital signal to be a one which indicates that there exists no digital signal identical to the copyrighted digital signal;
storing the digital signal in which the copy bit flag is set;
reading the stored digital signal; and
setting in the read digital signal a copy bit flag which indicates that there exists a digital signal identical to the copyrighted digital signal.
Also the above object can be attained by providing a program recording medium having recorded therein a control program under which:
a copyrighted digital is read;
a copy bit flag which indicates whether there exists any digital signal identical to the copyrighted digital signal is set to be a one which indicates that there exists no digital signal identical to the copyrighted digital signal;
the digital signal in which the copy bit flag is set is stored;
the stored digital signal is read;
a copy bit flag which indicates that there exists a digital signal identical to the copyrighted digital signal is set in the read digital signal; and
the read signal is provided as an output.
Also the above object can be attained by providing a digital signal recording apparatus for recording a digital signal stored therein into a recording medium, comprising:
means for storing a digital signal having added thereto a copy bit flag which indicates whether there exists any digital signal identical to the stored digital signal;
means for judging whether the copy bit flag added to the stored digital signal indicates that there exists a digital signal equivalent to the stored digital signal or that there exists no digital signal equivalent to the stored digital signal; and
means for ceasing to record into the recording medium a digital signal stored in the storing means when the judging means judges that there exists a digital signal equivalent to the stored digital signal, whereas recording into the recording medium a digital signal stored in the storing means when the judging means judges that there exists no digital signal equivalent to the stored digital signal.
Also the above object can be attained by providing a digital signal recording method of recording a digital signal stored therein into a recording medium, comprising, according to the present invention, the steps of:
storing a digital signal having added thereto a copy bit flag which indicates whether there exists any digital signal identical to the stored digital signal;
judging whether the copy bit flag added to the stored digital signal indicates that there exists a digital signal equivalent to the stored digital signal or that there exists no digital signal equivalent to the stored digital signal; and
ceasing to record into the recording medium a digital signal stored in the storing means when it is judged that there exists a digital signal equivalent to the stored digital signal, whereas recording into the recording medium a digital signal stored in the storing means when it is judged that there exists no digital signal equivalent to the stored digital signal.
Also the above object can be attained by providing a program recording medium having recorded therein a control program under which:
a digital signal having added thereto a copy bit flag indicating whether there exist digital signals equivalent to each other;
it is judged whether the copy bit flag added in the digital signal indicates that there exists a digital signal equivalent to the digital signal or that there exists no digital signal equivalent to the digital signal; and
recording into the recording medium of a digital signal stored in the storing means is ceased when it is judged that the copy bit flag indicates that there exists a digital signal equivalent to the digital signal, whereas a digital signal stored in the storing means is recorded into the recording medium when it is judged that the copy bit flag indicates that there exists no digital signal equivalent to the digital signal.
Also the above object can be attained by providing a digital signal recording apparatus comprising according to the present invention:
means for storing an original digital signal having added thereto a copy bit flag indicating that there exists a digital signal equivalent to the original digital signal;
means for deleting the digital signal equivalent to the original digital signal from a recording medium in which that digital signal is recorded; and
means for rewriting, when deleting the digital signal in consideration by the deleting means, the copy bit flag in the storing means to a one which indicates that there exists no digital signal equivalent to the original digital signal.
Also the above object can be attained by providing a digital signal storing method comprising, according to the present invention, the steps of:
storing an original digital signal having added thereto a copy bit flag indicating that there exists a digital signal equivalent to the original digital signal;
deleting the digital signal equivalent to the original digital signal from a recording medium in which that digital signal is recorded; and
rewriting, when deleting the digital signal in consideration by the deleting means, the copy bit flag in the storing means to a one which indicates that there exists no digital signal equivalent to the original digital signal.
Also the above object can be attained by providing a program recording medium having recorded therein a control program under which a digital signal having added thereto a copy bit flag indicating that there exists a digital signal equivalent to the digital signal is stored;
the digital signal equivalent to the stored digital signal is deleted from a recording medium in which it is recorded; and
the copy bit flag in the storing means is rewritten, when the digital signal equivalent to the stored digital signal is deleted, to a one indicating that there exists no digital signal equivalent to the stored digital signal.
These objects and other objects, features and advantages of the present intention will become more apparent from the following detailed description of the preferred embodiments of the present invention when taken in conjunction with the accompanying drawings.